This invention relates to the synthesis of compounds of formula 1 which are known to be useful for a variety of purposes including use as intermediates in the synthesis of prostaglandins. In the above formula, R.sub.1 defined below, includes a member of the group consisting of alkyl, alkenyl, and alkynyl groups of from 2 to 9 carbon atoms which can be substituted by a terminal carboxyl or carboalkoxy group (-COOR') in which the alkyl group (R') is from one to 6 carbon atoms.
In J. Am. Chem. Soc. 95:5, Mar. 7, 1973, pp 1676-7 there is described a synthesis of prostaglandin E.sub.1 in which 2(6-carboethoxyhexyl)-4 -(2-hydroxy)-2-cyclopenten-1-one (i.e., formula 2 were R.sub.1 is the 6 -carboethoxyhexyl group) is used as an intermediate.